Silicon carbide (SiC) is a wide gap semiconductor having excellent physical properties such as an approximately triple band gap, an approximately double saturated drift velocity, and an approximately decuple dielectric breakdown field strength as compared with silicon (Si). Consequently, silicon carbide has been developed as a material of a power semiconductor device, and Schottky barrier diodes manufactured by using SiC have been on the market.
FIG. 3 is a cross-sectional view showing a conventional SiC Schottky barrier diode. The SiC Schottky barrier diode 11 is mainly composed of a SiC single-crystal substrate 2 that is a slice in a wafer shape of SiC bulk single crystal grown by a sublimation method or the like, a SiC epitaxial film 3 grown from the surface of the SiC single-crystal substrate 2 by the chemical vapor deposition (CVD), a Schottky electrode 4 formed on the surface of the SiC epitaxial film 3 by a method such as sputtering or vacuum deposition, and an ohmic electrode 7 formed on the other surface of the SiC single-crystal substrate 2 (Patent documents 1 and 2).
A pad electrode 6 is formed on the Schottky electrode 4. An electrical connection to an external circuit such as a circuit board can be made via the pad electrode 6 by a method such as wire bonding, solder connection or terminal connection.    Patent document 1: Japanese Patent Application Laid-Open    Publication No. 2000-299479    Patent document 2: Japanese Patent Application Laid-Open    Publication No. 2003-243323